assuming efficiency of each man to dig trench, in one day, for one hour is constant,

so one man, working for one hour in one day can dig 1.5 m
so 8 men, working 3 hours a day and will take, say $d$ number of days and efficiency will be constant. so,
$\frac32=\frac{220}{8\times3\times d}$
$\implies d=\frac{55}9=6.12$
Commodore Matthew C. Perry
Perry was warmly received by Japanese officials who had acquiesced and prepared a treaty that fulfilled many of Fillmore's demands. The Treaty of Kanagawa ensured the protection of American property and opened the ports of Hakodate and Shimoda to trade.
They are elected for a period of 2 years
Zero times that the word slavery appears in the constitution.
This answer would be A because